#include "support.h"
#include "board.h"

#include "uart.h"

#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)

#define WAIT_FOR_XMITR \
        do { \
                lsr = REG8(UART_BASE + UART_LSR); \
        } while ((lsr & BOTH_EMPTY) != BOTH_EMPTY)

#define WAIT_FOR_THRE \
        do { \
                lsr = REG8(UART_BASE + UART_LSR); \
        } while ((lsr & UART_LSR_THRE) != UART_LSR_THRE)

#define CHECK_FOR_CHAR (REG8(UART_BASE + UART_LSR) & UART_LSR_DR)

#define WAIT_FOR_CHAR \
         do { \
                lsr = REG8(UART_BASE + UART_LSR); \
         } while ((lsr & UART_LSR_DR) != UART_LSR_DR)

#define UART_TX_BUFF_LEN 32
#define UART_TX_BUFF_MASK (UART_TX_BUFF_LEN -1)

void uart_init(void) {
	int divisor;

	/* Reset receiver and transmiter */
	/* Set RX interrupt for each byte */
	REG8(UART_BASE + UART_FCR) = UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT | UART_FCR_TRIGGER_1;

	/* Enable RX interrupt */
	REG8(UART_BASE + UART_IER) = UART_IER_RDI | UART_IER_THRI;

	/* Set 8 bit char, 1 stop bit, no parity */
	REG8(UART_BASE + UART_LCR) = UART_LCR_WLEN8 & ~(UART_LCR_STOP | UART_LCR_PARITY);

	/* Set baud rate */
	divisor = IN_CLK / (16 * UART_BAUD_RATE);
	REG8(UART_BASE + UART_LCR) |= UART_LCR_DLAB;
	REG8(UART_BASE + UART_DLL) = divisor & 0x000000ff;
	REG8(UART_BASE + UART_DLM) = (divisor >> 8) & 0x000000ff;
	REG8(UART_BASE + UART_LCR) &= ~(UART_LCR_DLAB);

	return;
}

void uart_putc(char c) {
	unsigned char lsr;

	WAIT_FOR_THRE;
	REG8(UART_BASE + UART_TX) = c;
	if(c == '\n') {
		WAIT_FOR_THRE;
		REG8(UART_BASE + UART_TX) = '\r';
	}
	WAIT_FOR_XMITR;
}


char uart_getc(void) {
	unsigned char lsr;
	char c;

	WAIT_FOR_CHAR;
	c = REG8(UART_BASE + UART_RX);
	return c;
}

void uart_print_str(char *p) {
	while(*p != 0) {
		uart_putc(*p);
		p++;
	}
}

void uart_put_int(int n) {
	int  a;
	char c;
	if (n<0) {
		uart_putc('-');
		n = -n;
	}

	a = n/10;
	if(a) uart_put_int(a);

	c = '0' + (n % 10);
	uart_putc(c);
}


